When Borg drones attempted to assimilate DoctorPhlox of the Enterprise NX-01, his Denobulanimmune system was able to fight off the nanoprobes long enough for him to discover that they were vulnerable to omicron particles, although the scale of the radiation dose required to destroy every nanoprobe in his body in one blast before they could adapt to the treatment means that this method cannot be used against the assimilation process on a larger scale, Phlox only surviving due to the immune system that allowed him to resist them for so long. (ENT: "Regeneration")